(1) Field of the Invention
The present invention relates to a method for affixing an adhesive tape to a semiconductor wafer subjected to surface treatment in order to protect a surface of the semiconductor wafer, and an apparatus using this method.
(2) Description of the Related Art
JP-A 2004-025438 discloses one example of a technique for affixing an adhesive tape to a semiconductor wafer. According to this technique, an adhesive tape is separated from a separator, and is supplied onto a semiconductor wafer placed on a chuck table. Then, the adhesive tape is affixed to a surface of the semiconductor wafer by means of an affixation roller.
In such a technique, however, a semiconductor wafer is placed on the chuck table one by one; consequently, an adhesive tape affixing operation is performed intermittently. Hence, supply of an adhesive tape is stopped during an interval between adhesive tape affixing operations. More specifically, in a case that a separator attached to an adhesive tape is separated from the adhesive tape, if the separator separating operation is stopped temporarily, a streak-shaped whitish mark (separation stop mark) is put on an adhesion face of the adhesive tape at a separation point of the separator across the adhesive tape.
At the separation stop mark, the adhesion layer is varied in thickness. Hence, if the adhesive tape is affixed to a semiconductor wafer in a state that the separation stop mark overlaps with a surface of the semiconductor wafer, trouble is caused in a subsequent process such as a back grinding process in some cases. In particular, a semiconductor wafer becomes thinner and thinner in recent years. Consequently, if the semiconductor wafer is varied in thickness due to minute variation in thickness of the adhesion layer, trouble caused by an influence of the variation in the thickness of the semiconductor wafer becomes conspicuous in a subsequent process.